Vaccines are doing their jobs preventing disease and death, and even bringing down societal costs, according to a new study in Pediatrics.
But another study, published in the same journal issue, found that public health campaigns touting vaccines' effectiveness and debunking the links between autism and other health risks might actually be backfiring, and convincing parents to skip the shots for their kids.
"Corrections of misperceptions about controversial issues like vaccines may be counterproductive in some populations," wrote the researchers behind one of the studies, led by Dr. Brendan Nyhan, a health care researcher at Dartmouth College in Hanover N.H. "The best response to false beliefs is not necessarily providing correct information."
Both studies were published in the March 3 issue of Pediatrics.
For the study looking at economic impact of vaccines, researchers looked at data on vaccination and disease rates collected from 2005 to 2009, and found following the current childhood immunization schedule prevented 20 million cases of disease, about 42,000 deaths and saved billions of dollars in medical and other societal costs.
The study looked at nine recommended childhood vaccines excluding the flu shot: diphtheria and tetanus toxoids and acellular pertussis (DTaP), Haemophilus influenzae type b conjugate (Hib), polio, measles/mumps/rubella (MMR), hepatitis B, chickenpox, pneumococcal vaccine, hepatitis A and rotavirus vaccines.
The CDC created a schedule for these vaccines that should be followed from the child's birth to when he or she are 6 years old.
The researchers found the vaccines reduced direct medical costs by $13.5 billion, including money spent to treat infections and disease complications. The overall societal costs -- which included supplies and special education for children disabled by diseases, and productivity losses caused by premature death -- totaled $68.8 billion.
For every dollar spent on childhood vaccines, at least $10 in societal costs were saved.
"The increased number of vaccines incorporated into the early childhood schedule has raised questions about the value of the vaccination series," wrote the study's authors, led by Dr. Fangjun Zhou, a researcher at the National Immunization Services Division of the Centers for Disease Control and Prevention (CDC) in Atlanta. "The vaccines currently recommended for young children represent not only a major public health victory in terms of disease prevention, but also an excellent public health 'buy' in terms of dollars and cents."
However, childhood vaccinations have been a controversial topic for many parents, despite science showing they are safe and effective at preventing diseases.
The CDC warned in December that once-eliminated measles is back in elevated numbers -- about 175 cases in 2013, compared to the typical 60 each year. Anti-vaccination beliefs were suspected to be behind the rate increases, including an oft-debunked link perpetuated by a British researcher whose since-retracted study found a link between the MMR vaccine and autism risk.
"Clusters of people with like-minded beliefs leading them to forgo vaccines can leave them susceptible to outbreaks when measles is imported from elsewhere," Dr. Anne Schuchat, director of the National Center for Immunization and Respiratory Diseases, said in September 2013.
Rates of whooping cough, which is vaccinated against starting adolescence, have also risen in recent years.
But, a dose of evidence-based medicine doesn't seem to be convincing some parents to get their kids vaccinated.
To find out why, Nyhan and his team conducted a trial and exposed parents to one of four different campaigns promoting the MMR vaccine based on strategies commonly used by public health officials.
The first campaign attempted to correct misinformation by explaining the lack of evidence that the MMR vaccine causes autism. The second presented information on the risk of measles in text form. The third showed powerful images of children who developed diseases that could be prevented by the MMR vaccine, and the fourth focused on a dramatic story of one infant who almost died of measles.
A control group was given a sheet of text explaining the costs and benefits of bird feeding, completely unrelated to vaccines.
Participants were asked whether they disagreed or agreed that some vaccines cause autism in healthy children, whether children will "suffer serious side effects" from the MMR vaccine, and how likely they would be to give their future child a vaccine.
None of the designed public health messages increased parental intent to get their child vaccinated.
Debunking the claims between the measles vaccine and autism appeared to successfully reduce misperceptions about the shot causing the developmental disorder. But, compared to the group given the bird-feeding fact sheet, they were less likely to commit to vaccinating their future kids, which was especially the case for parents who already had unfavorable attitudes towards vaccines.
The images of children who had the diseases and the story of a child who almost died from measles actually backfired, increasing the misconception that vaccines cause autism and serious side effects, respectively.
The researchers suspected the CDC debunking the autism claims backfired and got parents to think of other concerns to justify anti-vaccine beliefs. The images and dramatic narrative of sick kids might have backfired by priming parents to think of more dangers and associate them with vaccines.
The study only looked at intention to vaccinate, and not whether or not parents actually got heir kids vaccinated. It's not clear how much their attitudes would match with reality.
But the researchers concluded that the study shows these campaigns have to be tested first among especially resistant groups. Going for a subtle approach instead of scaring parents might be more effective.
"These results suggest the need to carefully test vaccination messaging before making it public," they said.